The Centinela Mining District (CMD), Atacama Desert (northern Chile), includes several mid-late Eocene porphyry Cu deposits that contains supergene mineralization and provides access to a record of gravel deposits that host syn-sedimentary exotic Cu mineralized bodies. By studying these gravels, we reconstruct the unroofing history and constrain the geomorphological conditions that produced supergene and exotic Cu mineralization. We present an integrated study based on stratigraphic and sedimentological data, lithology clast counts, 40 Ar/ 39 Ar and U/Pb ages from interbedded tuff layers and U/Pb detrital zircon geochronology data. To relate the gravel deposition episodes to the timing of the supergene mineralization, we provide in-situ and exotic supergene mineral ages (40Ar/39Ar and K-Ar). Six gravel units were deposited between the mid-Eocene and the mid-Miocene. The Esperanza gravels were deposited concurrently with the emplacement of porphyry Cu deposits at depth. The subsequent Tesoro I, II and III and Atravesado gravels register the unroofing of these deposits, from the advanced argillic zone to the sericitic and prophylitic hypogene zones. The Arrieros gravels register landscape pediplanation, that is, denudational removal and wear of the landscape to base level on a relatively stable tectonic regime, occurring roughly contemporaneous with supergene activity. The supergene mineral ages of the CMD define a time span (ca. 25-12 Ma) during which most of the supergene ages cluster in northern Chile. This time span corresponds with a period of warm and humid climate conditions in the southern hemisphere. We conclude that landscape pediplanation favours supergene mineralization and helps preserve the former supergene mineralized zones from significant erosion. Low erosion rates during pediplanation may constitute a necessary condition for the efficiency of the supergene processes in such semi-arid climate.

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The collection of accurate geologic data is critical in minerals exploration. The successful visualization, integration, and interpretation of quantitative vein abundance data, associated selvages of wall-rock alteration mineralogy, sulfide mineral proportions, and metal zoning facilitate the path to discovery and orebody delineation. The application of the Anaconda method, developed by the Anaconda Copper Mining Company geologists in the 1960s, to geologic mapping and drill core logging has facilitated the discovery and resource expansion in the giant Alpala porphyry Cu-Au-Ag deposit in northern Ecuador and the Cortadera porphyry Cu-Au-Mo deposit cluster in northern Chile. In both porphyry systems, high-grade zones have been targeted through the delineation of an intrusion and vein chronology that allows for the recognition of early-stage causal intrusions, zones of abundant porphyry-style quartz veins, and elevated chalcopyrite to pyrite ratios. Increased amounts of molybdenum, as molybdenite along fractures and in quartz veins, as well as anhydrite veins and disseminations, correlate with proximity to the deposit cores. The field-based methods presented in this article have proven useful in porphyry exploration for decades. The application of the Anaconda method of geologic mapping and core logging by geologists can assist in the targeting of high-grade cores of deposits and improved estimation of metal resources.